Name
EXT_clip_volume_hint
Name Strings
GL_EXT_clip_volume_hint
Version
Microsoft revision 1.00, April 17, 1996 (hockl)
$Date: 1999/12/28 01:40:35 $ $Revision: 1.4 $
Number
79
Dependencies
None.
Overview
EXT_clip_volume_hint provides a mechanism for applications to
indicate that they do not require clip volume clipping for
primitives. It allows applications to maximize performance in
situations where they know that clipping is unnecessary.
EXT_clip_volume_hint is only an indication, though, and
implementations are free to ignore it.
New Procedures and Functions
None.
New Tokens
Accepted by the target parameter of Hint and the pname parameter of
GetBooleanv, GetDoublev, GetFloatv and GetIntegerv:
CLIP_VOLUME_CLIPPING_HINT_EXT 0x80F0
Additions to Chapter 2 of the GL Specification (OpenGL Operation)
Before the last paragraph of Section 2.11, 'Clipping,' the following
text is added:
The EXT_clip_volume_hint extension can be used to indicate that
a primitive falls inside the current clip volume. In this case,
an implementation might not clip the primitive to the clip
volume, and the behavior of the GL is undefined if the primitive
extends beyond the clip volume.
In the fourth (clipping) paragraph of Section 2.12, 'Current Raster
Position,' the following text is added before the last sentence
"Figure 2.7 summarizes..."
Raster position clipping is not affected by the
CLIP_VOLUME_CLIPPING_HINT_EXT hint in the EXT_clip_volume_hint
extension.
Additions to Chapter 3 of the GL Specification (Rasterization)
None.
Additions to Chapter 4 of the GL Specification (Per-Fragment
Operations and the Framebuffer)
None.
Additions to Chapter 5 of the GL Specification (Special Functions)
Section 5.6, 'Hints,' should be changed to add the following
hint description:
CLIP_VOLUME_CLIPPING_HINT_EXT, indicating whether clipping to
the clip volume is necessary.
Additions to Chapter 6 of the GL Specification (State and State
Requests)
In table 6.18, 'Hints,' the following entry is added:
CLIP_VOLUME_CLIPPING_HINT_EXT|Z3|GetIntegerv|DONT_CARE|
Clip volume clipping hint|5.6|hint
Revision History
----------------
Original draft, revision 0.9, March 1, 1996 (drewb)
Created.
Minor revision, revision 0.91, March 8, 1996 (drewb)
Hint revision, revision 0.95, April 12, 1996 (drewb)
Changed from Enable-based to Hint-based. Clarified
behavior of RasterPos.
More revision, revision 0.96, April 16, 1996 (hockl)
Changed extension and enumerant names. Added robustness.
Changed it to have no effect on RasterPos.
More revision, revision 1.00, April 17, 1996 (hockl)
Removed robustness requirement.